DWT is SWT port to D. So almost all the api/docs on SWT will also
work with D.
I usualy just type "SWT examples" or "SWT use ComboBox" in
google, then port it to D. If there are any differences, I just
open the source or DDoc to compare the D version with the java
version.
Regarding the installation, DWT is a library so after building
it, it creates a *.lib file which can be used just as any other
library files. Also the git downloads the source files which can
be used for importing in the code. If you just type "dmd" it
shows the command line options for specifying the library and
include folders. Other way is to edit the SC.ini (comes with DMD)
file and specify them in it.
I do most of my work in windows and I can give more details if
you want. I am not 100% sure for ubuntu, probably ubuntu experts
will reply.
good luck